U.S. patent application Ser. No. 08/854,042, which is assigned to the assignee of this application, describes an article transfer device, which is usually referred to as a lehr loader or a stacker, that is intended to transfer a plurality of freshly formed glass containers, in a linear array, and in unison, transversely of a conveyor carrying the containers into a heat treating device, which is usually called an annealing lehr. U.S. Pat. No. 5,044,488 (Bolin), the disclosure of which is incorporated by reference herein, describes an alternative version of a lehr loader or stacker and describes the required three-axis motion that a pusher bar of the lehr loader or stacker must undergo during each container transfer cycle.
A glass container lehr loader of the type described is serviced by an infeed conveyor, usually called a cross-conveyor, whose upper, conveying flight must be carefully positioned in elevation to be able to present the container for proper transfer to a conveyor of the lehr by the lehr loader. This requirement may be met by providing the cross conveyor with a plurality of right angle drive gearboxes, many of which are positioned at relatively inaccessible locations, and in any case in a relatively high temperature environment due to the proximity of the cross-conveyor to the lehr and the latent heat of the containers at the inlet to the lehr. These right angle drive gearboxes need only be used intermittently, however, prior to a change in the position of the elevation of the cross-conveyor at one or more locations, and they are only used to transfer fairly low levels of torque, typically being manufally operated. Hence, these right angle drive gearboxes need not be massive or rugged, and a fairly simple and relatively inexpensive gearbox is usually more than adequate for this service. However, it is important that such a gearbox be easy to take apart for maintenance and lubrication and that it be closed during operation to keep dust and foreign particles out of the gears, and to keep lubricant in contact therewith.